msem-instigator

Whenever another creature you control dies, each opponent loses 1 life and you gain 1 life. Then you may pay {B}. If you do, Disciple of Myriad Fates becomes a copy of that creature, except it has this ability.

Flying
When Hallowed Executioner enters, it deals 2 damage to each creature without flying.

Other creatures you control named Starfall Dancer get +2/+2.

When Doomed Traveler dies, create a 1/1 white Spirit creature token with flying.

Whenever a creature dies, put a +1/+1 counter on Bog Apex.

[+1]: Distribute two +1/+1 counters among any number of target creatures you control.
[–1]: Create two 1/1 white Monk creature tokens.
[–6]: Until your next turn, you choose which creatures attack or block and how those creatures attack or block.

Defender, reach
When Soothevine Elemental enters, draw a card.

Tap two untapped creatures you control: Harmonize. (Trigger up to one harmony of one permanent you control.)
Harmony — Choose one —
• Soul of New Alores becomes a creature in addition to its other types until end of turn.
• Put two +1/+1 counters on target permanent.

{T}: Add {U} or {B}. You lose 1 life unless you have less life than an opponent.

Target creature you control gets +1/+1 and gains lifelink until end of turn. It fights target creature you don't control.

Whenever Forgotten King's Mask enters or equipped creature dies, attach it to target creature you control.
Equipped creature has base power and toughness 5/5 and is a Noble in addition to its other types.
{1}{R}, Discard two cards: Create a 1/1 white Human creature token and attach Forgotten King's Mask to it. Activate only as a sorcery.

Motley Crew has no name while it's being cast. (It will always make first contact.)
{2}{R}: Creatures you control named Motley Crew get +1/+0 until end of turn.

Target player creates two 1/1 white Spirit creature tokens with flying.
Fabled {3}{W}{W} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that player.)

Flying
When Fickle Songstress enters, target opponent gains control of it.
Whenever you lose life, if you don't own Fickle Songstress, its owner gains control of it.

Bloodprice {2}{B} (You may cast this card by sacrificing a creature and paying its bloodprice.)
Create X 2/2 black Demon creature tokens, where X is one plus the number of creatures that died this turn.

Trample
Lotusleaf Blade gets +1/+1 as long as you control another Warrior.

Counter target instant or sorcery spell you don't control unless its controller copies it twice. You gain control of those copies and may choose new targets for them.

Speckled Outcast has menace as long as it's enchanted.

Haste
Glorious end — When Warband Lieutenant dies, if it was tapped, put a +1/+1 counter on another target creature you control.

Hexproof

Exchange control of two target permanents that share a permanent type.
Lifecycle {3} ({3}, Discard this card: Create two tapped 1/1 colorless Elemental creature tokens.)

Destroy target creature if it has the least power or is tied for least power among creatures on the battlefield.
Memento {3}{B}{B} (You may cast this from your graveyard for {3}{B}{B}. If you do, put it onto the battlefield transformed after it resolves. Exile it if it would leave the battlefield or not resolve.)

Pelagic Hydra enters with seven +1/+1 counters on it.
{1}{G}: Put a +1/+1 counter on Pelagic Hydra.
Remove a +1/+1 counter from Pelagic Hydra: It deals 1 damage to target creature blocking or blocked by it.

This spell costs {1} less to cast for each creature and/or planeswalker card in your graveyard.
Return target creature or planeswalker card from your graveyard to the battlefield.

Reach
As Celestial Principality enters, choose a number.
Noncreature spells with mana value equal to the chosen number can't be cast.